↵* In both treatment groups the lowest age at entry was 2.0 hours and the range of a/APo2 was 0.22 to 0.35 for infants fulfilling the entry criteria strictly (n = 54). One infant in each treatment group was randomized before 2 hours; the late-treated also had a/APo2 <0.22. One infant treated early and 3 infants treated late had a/APo2 >0.35.